Get a garden hose thread pressure gauge. Turn off the WHs, or move to vacation. Monitor the water pressure.
You can get one with a tattletale/lazy hand to record the peak. Now that hand going up is not for sure that your water pressure went that high. Vibration can make that hand move.
If you want, you can take a movie of the pressure gauge with your cellphone.
Gauge can go on hose spigot, laundry tap, or the drain on a water heater.
It seems unfair to try to get plumbers to come out for free to tell you that you don't need a PRV, but only a thermal expansion tank.
You can get one with a tattletale/lazy hand to record the peak. Now that hand going up is not for sure that your water pressure went that high. Vibration can make that hand move.
Watts 3/4 in. Plastic Water Pressure Test Gauge DP IWTG - The Home Depot
When you choose this hose connection gauge, you can rest assured that you're getting a quality product to test water supply pressures within a distribution system. Its red indicator hand holds at the highest reading registered for detection of thermal expansion pressure surges. Rubber garden...
www.homedepot.com
Gauge can go on hose spigot, laundry tap, or the drain on a water heater.
It seems unfair to try to get plumbers to come out for free to tell you that you don't need a PRV, but only a thermal expansion tank.